<template>
  <!-- 商品分类导航 -->
  <div class="type-nav">
    <div class="container">
      <div @mouseleave="leaveIndex" @mouseenter="enterShow">
        <h2 class="all">全部商品分类</h2>

        <!-- 过渡动画 -->
        <transition name="sort">
          <div class="sort" v-show="show">
            <div class="all-sort-list2" @click="goSearch">
              <!-- 一级分类 -->
              <div
                class="item"
                v-for="(c1, index) in categoryList"
                :key="c1.categoryId"
                :class="{ cur: currentIndex === index }"
              >
                <h3 @mouseenter="changeIndex(index)">
                  <a
                    :data-categoryName="c1.categoryName"
                    :data-category1Id="c1.categoryId"
                    >{{ c1.categoryName }}</a
                  >
                </h3>

                <!-- 二级分类 -->
                <div
                  class="item-list clearfix"
                  :style="{
                    display: currentIndex === index ? 'block' : 'none',
                  }"
                >
                  <div
                    class="subitem"
                    v-for="(c2, index) in c1.categoryChild"
                    :key="c2.categoryId"
                  >
                    <dl class="fore">
                      <dt>
                        <a
                          :data-categoryName="c2.categoryName"
                          :data-category2Id="c2.categoryId"
                          >{{ c2.categoryName }}</a
                        >
                      </dt>

                      <!-- 三级分类 -->
                      <dd>
                        <em
                          v-for="(c3, index) in c2.categoryChild"
                          :key="c3.categoryId"
                        >
                          <a
                            :data-categoryName="c3.categoryName"
                            :data-category3Id="c3.categoryId"
                            >{{ c3.categoryName }}</a
                          >
                        </em>
                      </dd>
                    </dl>
                  </div>
                </div>
              </div>
            </div>
          </div>
        </transition>
      </div>

      <nav class="nav">
        <a href="###">服装城</a>
        <a href="###">美妆馆</a>
        <a href="###">尚品汇超市</a>
        <a href="###">全球购</a>
        <a href="###">闪购</a>
        <a href="###">团购</a>
        <a href="###">有趣</a>
        <a href="###">秒杀</a>
      </nav>
    </div>
  </div>
</template>

<script>
import { mapState } from "vuex";
// import _ from "lodash"; //引入了全部的lodash
import throttle from "lodash/throttle"; //按需引入

export default {
  name: "TypeNav",
  data() {
    return {
      currentIndex: -1, //存储用户鼠标放在哪个一级菜单的index
      show: true,
    };
  },

  computed: {
    ...mapState({
      categoryList: (state) => state.home.CategoryList,
    }),
  },

  methods: {
    // changeIndex(index) {
    //   this.currentIndex = index;
    // },
    // 鼠标进入，修改currentIndex，一级菜单背景改变
    changeIndex: throttle(function (index) {
      // 用户操作太快，当前回调函数可能出现卡顿现象，使用节流
      this.currentIndex = index;
    }, 50),

    // 鼠标滑出，修改currentIndex，一级菜单背景改变
    leaveIndex() {
      this.currentIndex = -1;
      if (this.$route.path != "/home" && this.$route.path != "/") {
        this.show = false;
      }
    },

    // 点击三级联动，跳转到search
    goSearch(params) {
      // 用事件委派存在的问题：所有的子节点都有该事件,点击的不一定是a标签，如何获取参数，
      // 把子节点中的a标签加上自定义属性，其余节点没有
      // 节点有一个dataset属性，可以获取节点的自定义属性与属性值
      let element = event.target; // 获取到当前这个触发事件的节点
      let { categoryname, category1id, category2id, category3id } =
        element.dataset;
      // 如果点击的标签有categoryname这个属性一定是a标签
      if (categoryname) {
        let location = { name: "search" };
        let query = { categoryName: categoryname };
        if (category1id) {
          query.category1Id = category1id;
        } else if (category2id) {
          query.category2Id = category2id;
        } else {
          query.category3Id = category3id;
        }
        // 判断有没有params参数，有也要一并传过去
        if (this.$route.params) {
          location.params = this.$route.params;
          location.query = query;
          this.$router.push(location);
        }
      }
    },

    // 在搜索页面，鼠标滑入全部商品
    enterShow() {
      if (this.$route.path != "/home") {
        this.show = true;
      }
    },
  },

  mounted() {
    //  控制typeNav的List显示或隐藏
    // console.log(this.$route.path)
    if (this.$route.path === "/search") {
      this.show = false;
    }
  },
};
</script>

<style  lang="css" scoped>
.type-nav {
  border-bottom: 2px solid #e1251b;
}
.container {
  width: 1200px;
  margin: 0 auto;
  display: flex;
  position: relative;
}
.all {
  width: 210px;
  height: 45px;
  background-color: #e1251b;
  line-height: 45px;
  text-align: center;
  color: #fff;
  font-size: 14px;
  font-weight: bold;
}

.nav a {
  height: 45px;
  margin: 0 22px;
  line-height: 45px;
  font-size: 16px;
  color: #333;
}

.sort {
  position: absolute;
  left: 0;
  top: 45px;
  width: 210px;
  height: 511px;
  position: absolute;
  background: #fafafa;
  z-index: 999;
}
/* 过渡动画 */
.sort-enter {
  /* 开始状态（进入） */
  height: 0px;
}
.sort-enter-to {
  /* 过渡动画结束状态（进入 */
  height: 511px;
}
.sort-enter-active {
  /* 定义动画 的时间、速率 */
  transition: all 0.2s linear;
}
.sort-leave {
  /* 开始状态（离开） */
  height: 511px;
}
.sort-leave-to {
  /* 过渡动画结束状态（离开 */
  height: 0px;
}
.sort-leave-active {
  /* 定义动画 的时间、速率 */
  transition: all 0.2s linear;
}

/* .all-sort-list2 .item:hover{
  background: pink;
} */
.cur {
  background: pink;
}
.all-sort-list2 .item h3 {
  line-height: 30px;
  font-size: 14px;
  font-weight: 400;
  overflow: hidden;
  padding: 0 20px;
  margin: 0;
}
a {
  color: #333;
}

.item-list {
  display: none;
  position: absolute;
  width: 734px;
  min-height: 460px;
  _height: 200px;
  background: #f7f7f7;
  left: 210px;
  border: 1px solid #ddd;
  top: 0;
  z-index: 9999 !important;
}
.subitem {
  float: left;
  width: 650px;
  padding: 0 4px 0 8px;
}
dl {
  border-top: 1px solid #eee;
  padding: 6px 0;
  overflow: hidden;
  zoom: 1;
}
.fore {
  border-top: 0;
}

dt {
  float: left;
  width: 54px;
  line-height: 22px;
  text-align: right;
  padding: 3px 6px 0 0;
  font-weight: 700;
}

dd {
  float: left;
  width: 415px;
  padding: 3px 0 0;
  overflow: hidden;
}
dd em {
  float: left;
  height: 14px;
  line-height: 14px;
  padding: 0 8px;
  margin-top: 5px;
  border-left: 1px solid #ccc;
}

/* .item:hover .item-list {
  display: block;
} */
</style>